Induction cooker is one of the electric family appliance, many types of induction cooker are sold in market, however, the heating surface(s) of traditional induction cookers with one or more heating surfaces is/are in a plate, and the food only can be heated by one surface; Additionally, traditional cookers with one or more heating surfaces are heated by heat conduction or heat radiation of the electric tube, thus the pans or heating plates have lower heating effect, lower power effect and long pre-heating time. because the contacting heating conduction, the pans or the heating plates of traditional cookers are easy to be distorted, and then lower the heating speed and the food is cooked un-uniformity.
Besides the above disadvantages, the induction cookers in market usually have no temperature detecting function; or some may has detecting function, but because the temperature detecting device are embedded under the heating board, while the heating board are usually made by low thermal conduction material such as crystallite glass, so the temperature detecting is not precise. On the other side, to make the best of time, we usually need to simmer (such as bone soup) and quick cooking (such as fried dish) at the same time in making food, traditional cooker with double heating surfaces needed to has a heating device and an operational device on each side respectively, in use, the operation device must be operated respectively, the operation is fussy. So both the induction cookers and traditional cookers have many defect.